Low-cost nucleic acid analysis, to detect HIV &HBV, has revolutionized screening of the blood supply. In spite of that new genetic sophistication, traditional blood group typing [ABO, Rh] is still performed, for the most part, via variations upon 80-year-old agglutination testing. Recently, the genetic variation which gives rise to the standard blood groups has been defined, and shown to be relatively simple. In parallel, it has been shown that, to enhance transfusion quality, the historical marker set might be expanded to include a more complete panel of 7 traits: [ABO, Rh, Duffy, Kidd, Kell, Dombrock &MNS] for which the underlying genetics are now known. These two parallel trends suggest that genetic testing has emerged as the future of blood group screening: but only if the genetic test can be delivered at roughly the same cost and level of technical simplicity as agglutination, or the current panel of nucleic acid based pathogen tests. We have observed that, with minor modification, the suite of biochemical, hardware &software technologies that we have developed for microarray based HLA-typing on raw blood could, instead, be transformed into low-cost technologies for blood-group typing, which we refer to as "The Transfusion-Chip". In this 6-month Phase I plan, we propose 2 Specific Aims as Milestones to justify a subsequent Phase II. SA1. Design &preliminary validation of 13-15 PCR reactions to be performed in parallel. All informative sites among the set of 7 blood marker genes will be amplified in parallel, to generate a dye-labeled amplicon set that is ready to be used for microarray hybridization. SA2. Microarray probe design, fabrication &preliminary validation. A Transfusion-Chip prototype will be designed and fabricated, to interrogate the informative sequence variations which define blood group variation among the set of 7 loci. The validation will employ amplified DNAs from SA1. Relation to a Follow-on Phase II. Completion of Phase I will yield a prototype PCR-based sample labeling reaction (that works on raw blood) and a prototype low-cost Transfusion-Chip microarray for DNA based blood-typing. Phase II will focus on refinement of the PCR and microarray designs, manufacturing scale-up, preliminary PCR kit fabrication and delivery of those materials to beta testers, comprising 3-4 top blood labs: to compare Transfusion-Chip performance to serological typing and to the competing microarray and PCR tests. Public Health Narrative. Genetic testing for pathogen contamination has revolutionized the safety of the blood supply, yet analogous DNA based testing of the underlying blood groups has lagged-behind, due to cost and complexity. A microarray-based approach to blood group typing that we propose here, will allow blood type analysis to be modernized, by exploiting two decades worth of blood group genetics: allowing analysis of blood group antigen variation, in a way that is more complete than can be obtained by serology, at a cost and level of technical simplicity that is as practical as that of blood pathogen screening. The resulting technology will not only reduce the cost of blood supply testing in the US, but we propose, will enable a new generation of enhanced, DNA-based blood group typing in the developing world. PUBLIC HEALTH RELEVANCE: A microarray-based approach to blood group typing that we propose here, will allow blood type analysis to be modernized, by exploiting two decades worth of blood group genetics: allowing analysis of blood group antigen variation, in a way that is more complete than can be obtained by serology, at a cost and level of technical simplicity that is as practical as that of blood pathogen screening. The resulting technology will not only reduce the cost of blood supply testing in the US, but we propose, will enable a new generation of enhanced, DNA-based blood group typing in the developing world.